Related papers: HD 210111: a new lambda Bootis type SB system

We present here 55 short period PCEBs containing a hot WD and a low-mass MS. Based on the photometric data from ZTF DR19, the light curves are analyzed for about 200 WDMS binaries with emission line(s) identified from SDSS or LAMOST…

The results of the abundance analyses of six lambda Bootis stars are presented. For three stars, the impact of individual ODFs and various treatments of convection in the calculactions of the model atmospheres are investigated.

ASASSN-13db is a M5-type star with a protoplanetary disk, the lowest mass star known to experience accretion outbursts. Since its discovery in 2013, it has experienced two outbursts, the second of which started in November 2014 and lasted…

TIC 322208686 is known to be a detached binary that exhibits two types of variability: pulsation and eclipse. We present the physical properties of the target star using the short-cadence TESS data from sectors 24, 57, and 58, and our…

Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision continuous measurements of the CoRoT space…

We report the discovery of an unusual stellar system, SMSS J130522.47-293113.0. The optical spectrum is dominated by a blue continuum together with emission lines of hydrogen, neutral and ionized helium, and the N III, C III blend at around…

Binary systems made by a low-mass CO WD and a He-donor represent possible progenitors of explosive events via He-detonation, producing low-luminosity thermonuclear Supernovae with a peculiar nucleosynthetis. Recently, the binary system PTF…

We report detection of quasi-periodic (1.5 day) dimming of HD 240779, the solar-mass primary in a 5" visual binary (also TIC 284730577), by the Transiting Exoplanet Survey Satellite. This dimming, as has been shown for other "dipper" stars,…

The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (muchfuss) aims to discover subdwarf-B stars with massive compact companions such as overmassive white dwarfs (M > 1.0 M_sun), neutron stars or black holes.…

$\gamma$ Doradus stars are photometrically variable early F-type stars on or just above the main sequence in the Hertzsprung-Russell Diagram. They vary by as much as 0.1 mag on time scales an order of magnitude slower than the fundamental…

There are two accepted mechanisms to explain the origin of runaway OB-type stars: the Binary Supernova Scenario (BSS), and the Cluster Ejection Scenario (CES). In the former, a supernova explosion within a close binary ejects the secondary…

Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis…

We present key sample results of a systematic survey of the pulsation properties of models of hot B subdwarfs. We use equilibrium structures taken from detailed evolutionary sequences of solar metallicity (Z = 0.02) supplemented by grids of…

We present BVR observations and low-resolution spectra collected by the Kottamia Astronomical Observatory 1.88 m telescope (KAO) for the new pulsating star ASAS J063309+1810.8 (hereafter it will be called ASAS06+18). The photometric…

We present here the analysis of an extensive set of high resolution optical spectra of Plaskett's star (HD 47129). We use a disentangling method to separate the individual spectra of each star. We derive a new orbital solution and discuss…

{This paper presents detailed analysis and modelisation of the star HD17051 (alias $\iota$ Hor), which appears as a specially interesting case among exoplanet host stars. As most of these stars, $\iota$ Hor presents a metallicity excess…

We present a catalog of central engine properties, i.e., black hole mass (mbh) and accretion luminosity (ld), for a sample of 1077 blazars detected with the Fermi~Large Area Telescope. This includes broad emission line systems and blazars…

12 Bootis is a spectroscopic binary whose visual orbit has been resolved by interferometry. Though the physical parameters of the system have been determined with an excellent precision, the theoretical modelling of the components is still…

We present results on the second-faintest pulsating subdwarf B (sdB) star known, RAT J0455+1305, derived from photometric data obtained in 2009. It shows both short and long periods oscillations, theoretically assigned as pressure and…

LB-1 has variously been proposed as either an X-ray dim B-type star plus black hole (B+BH) binary, or a Be star plus an inflated stripped star (Be+Bstr) binary. The Space Telescope Imaging Spectrograph (STIS) on board HST was used to obtain…